Enclosures or housings for electric load centers, switches and other electrical components suffer from a number of limitations, including withstanding loading from environmental forces and difficulty in passing environmental qualification testing. Enclosures are intended to isolate and protect electrical equipment positioned within their confines from external environmental conditions such as dust, rain, oil, hose directed water and other environmental qualification design bases specified in industry standards and in Underwriters Laboratories standards such as UL-50 "Standards For Enclosures For Electrical Equipment.",1997. The enclosure is also intended to enable the user from outside the enclosure to activate, deactivate, or otherwise operate electrical equipment within it by engaging an internally positioned activating or disconnect mechanism (from an ON to OFF position and vice versa). Most importantly, the operation of the external handle cannot cause injury to the operator due to an electrical short or other abnormal condition caused by a failure of the environmental qualifications of the enclosure. The externally positioned handle which penetrates the wall of the enclosure to engage the internally positioned disconnect mechanism must also withstand the above-mentioned environmental loadings and qualification standards.
The prior art enclosures use a "standard" switch box enclosure and apply gasketing and sealants on the very edges of the enclosure (constituting the thickness of the material making up the enclosure) in an attempt to environmentally qualify the enclosure. The gasketing would be placed in contact with the cover or door when closed in an attempt to prevent the elements or contaminants from entering during its design lifetime. Thus, the function of the cover/door in the prior art standard enclosures is, in part, to provide strength, and protection from the elements and contaminants by pressing against a gasket positioned on the edges of the enclosure when the cover/door is closed. However, during the course of performing a Research and Development Program on developing and manufacturing a new and improved weatherproof enclosure, testing disclosed that when the above-described cover/door of the prior art standard enclosures was closed, it indented the gasket positioned on the edges of the box or enclosure to such a degree that the gasket or seal elastic limits were exceeded and also caused the seal to "pucker up", i.e. to be displaced or pushed off the edges of either or both of the base and the endcaps. Even when the elastic limits of the gasketing material was not initially exceeded by the operation of the cover/door, the gasket nonetheless lost its resilience over time as well as puckered up off the edge of the base and endcaps. The edges upon which the gasket was adhered would ultimately cause it to fail by cutting it during the repeated opening/closing cycles of the cover/door.
Further testing performed during the Research and Development Program revealed that the use of the prior art "flat" door/cover actually promoted the subsequent failure of the prior art enclosures when subjected to the industry standard test of the impingement of water flow from a high pressure hose. These failures occurred regardless of whether the gasketing material had earlier failed, or failed during the high pressure hose-down, or had not failed at all. More specifically, the cover deflected or deformed inward due to the force of the high pressure stream of water impinging upon the door/cover, thereby creating an internal partial vacuum which promoted water ingress into the enclosure. The environmental failure of the enclosure was caused by the ingress of water either through a breach in the gasketing that had failed, or the ingress of water around the gasketing that had puckered up and off, or by the ingress of water that had been vacuum pulled past non-failed gasketing into the interior of the enclosure.
A related problem of the prior art enclosure designs disclosed during the Research and Development Program, is that the methods of securing the endcaps of enclosures to the base of the enclosure typically are the source of the environmental failure of the enclosure due to the ingress of moisture and water. In some of the prior art designs, the edges of the endcaps at the location where they are mounted to the enclosure are typically welded together and therefore subject to subsequent failure during loading. If a sealant alone was used or was used together with welding, the sealant was so positioned or applied so as to be directly accessible from the interior and/or the exterior of the enclosure. By being directly accessible, the sealant was thereby subject to potentially accidental tearing or ripping during for example installation of interior components, wiring, maintenance, or repair. Thus, this type of design in the prior art further contributes to the environmental failure of the enclosure from the ingress of moisture and water and thereby subjecting the internal electrical components to catastrophic failure. Thus, the prior art designs included few if any design features to resist failure from environmental loading.
As is typical in many other prior art designs as discovered during the Research and Development Program, the cover/door frequently was not in proper alignment with the enclosure due to several possible causes including misalignment of hinges due to manufacturing tolerances, assembly inaccuracies, and imprecise riveting or welding or other mechanical means of affixing the hinges or other mechanisms to the cover/door and/or the enclosure. Such misalignment sometimes resulted in the rejection of the enclosure during manufacture due to quality control requirements/standards, or caused the environmental failure during its operating life. Such failures typically result from, and include, direct leakage into the enclosure through gaps between the enclosure and/or cover/door due to misalignment and failure of gasketing material intended to seal the cover/door due to tearing, displacement, or cutting due to improper compression from non-uniform pressure caused when the misaligned cover/door is closed against the enclosure.